1. Field of the Invention
The present invention relates to a technical field of an information retrieval apparatus for retrieving information such as a destination spot in a navigation device which displays a travel route of a mobile object such as a vehicle, names of famous places around the travel route and the like as well as a map so as to assist the driving of the mobile object.
2. Description of Related Art
At present, there is known a navigation device, which displays a position mark (guide mark) representing a current position of a mobile object on a map so as to guide a travel route to a destination spot based on the displayed map, as a position measuring device used for various mobiles such as a vehicle, an aircraft and a vessel. In such navigation devices, vehicle navigation devices to be mounted on vehicles are roughly divided into two types: a stand-alone type navigation device and a GPS (Global Positioning System) type navigation device.
The stand-alone type navigation system obtains a travel direction and a travel distance of a vehicle by means of independent sensors such as a speed sensor and an angular velocity sensor provided on the vehicle, and then calculates a current position of the vehicle by successively adding the obtained travel direction and travel distance to a reference point so as to display a position mark and a corresponding map on a display screen based on the calculated current position.
The GPS type navigation system receives a position measuring radio waves from a plurality of GPS satellites launched into space via a GPS receiver, and calculates a current position of the vehicle by a three-dimensional measuring method or a two-dimensional measuring method based on the received result so as to display a position mark and a corresponding map on a display screen based on the calculated current position.
Further, a so-called hybrid-type vehicle navigation device having both functions of the above-mentioned stand-alone type and GPS types navigation systems is recently known.
In addition, among the above respective vehicle navigation devices, there is also known a navigation device for superposing a scheduled travel route, which the vehicle plans to follow, on a map to be displayed together with famous places around the travel route.
According to the above respective vehicle navigation devices, since a user (i.e., driver) can know a current position of the vehicle and a map around the current position in connection with each other, he or she can reach the destination without getting lost even if he or she goes to the area for the first time.
On the other hand, in the above-mentioned vehicle navigation device, there is a case, for example, that the driving is started after a destination spot is set and a travel route to the destination spot is determined in advance. At this time, in setting the destination spot, a plurality of destination candidates are arranged in a hierarchical data structure, and the particular destination spot is set by successively searching the hierarchical structure for that particular destination in an interactive manner with the user.
Namely, according to the vehicle navigation device having the destination spot setting function, when a destination spot is set concretely, plural types of destination attribute names (for example, attribute names representing types of destination spots such as a golf course, a theme park and a restaurant. The hierarchy of the destination candidates composed of the attribute names is the first hierarchy) are first displayed, and the user selects a target attribute of the destination spot from those plural attribute names. Then, plural names of prefectures (the hierarchy of the destination candidates composed of prefecture names is the second hierarchy) in which facilities including the target destination spot exist are displayed. When a name of the target prefecture where the destination spot exists is selected, plural names of areas in the target prefectures (for example, the names of areas such as northern part and southern part. The hierarchy of the spot candidates including the area names is the third hierarchy) are displayed so that a name of a target area where the destination spot exists is selected from the plural area names. Next, plural names of cities/towns/villages existing in the target area (the hierarchy of the spot candidates including the names of cities/towns/villages is the fourth hierarchy) are displayed, and a name of the target city/town/village where the destination spot exists is selected. Then, finally, plural names of concrete facilities having the target attribute selected previously in the selected city/town/village are displayed as destination candidates, and the destination spot is selected from those displayed names of the facilities and set.
However, in the case where the above-described destination spot setting function of the, vehicle navigation device is used, a driver needs to change the displayed prefecture names until a desired prefecture name is displayed in order to select the prefecture name included in the second hierarchy, for example. Therefore, there arose a problem that unnecessary time is required for searching the target prefecture name.
As for this problem, in the vehicle navigation device capable of inputting information by using a voice recognizing function which is being put into practical use recently, all candidate names of prefectures should be vocally reproduced by the device until a desired prefecture name comes out. As a result, the required time becomes unnecessarily long and the driving is hindered because many unnecessary voices are heard.
Further, according to the above-mentioned destination spot setting function, it is always necessary to start selecting candidates from the first hierarchy then down to the deeper hierarchies. In this case, for example, even if a user already knows a name of city/town/village where the destination spot exists (belonging to the fourth hierarchy), the driver should unnecessarily start the selecting operation from the uppermost hierarchy, and hence unnecessary operation should be made.
In view of the above, an object of the present invention is to provide an information retrieving apparatus and an information retrieving method, which are capable of retrieving a desired destination spot information quickly, accurately and conveniently in a navigation device having a destination spot setting function using spot candidates data of hierarchical structure.
According to one aspect of the present invention, there is provided an information retrieving apparatus for retrieving target information from plural pieces of candidate information, including: a storage unit for storing the plural pieces of the candidate information in a hierarchical structure including m hierarchies (m is a natural number not less than 2): an input unit for inputting information; a judging unit for judging a correspondence of the inputted information with one of the plural pieces of the candidate information and for judging the hierarchy of the candidate information if the correspondence is obtained; and a retrieving unit for retrieving one of the plural pieces of the candidate information as a target information based on a judged result of the judging unit.
In accordance with the apparatus thus configured, the storage unit stores the plural pieces of the candidate information in a hierarchical structure including m hierarchies. A user can input information via the input unit. Then, the judging unit judges a correspondence of the inputted information with one of the plural pieces of the candidate information, and then judges the hierarchy of the candidate information if the correspondence is obtained. Thereafter, the retrieving unit retrieves one of the plural pieces of the candidate information as a target information based on a judged result of the judging unit.
Therefore, since a hierarchy of inputted candidate information is judged first and then the information is retrieved based on the judged result, it is possible to retrieve target information in the order of hierarchies, or alternatively possible to retrieve target information while skipping one or plural hierarchies and jumping from a hierarchy to a hierarchy. Consequently, a desired target information can be retrieved conveniently in the information retrieval apparatus.
The hierarchical structure may be arranged such that each piece of the candidate information belonging to (n+1)-th hierarchy (n is a natural number and n less than mxe2x88x921) is associated with one of the plural pieces of the candidate Information belonging to n-th hierarchy. With this arrangement, if candidate information in the upper hierarchy are different, candidate information in the lower hierarchy corresponding to the candidate information in the upper information are different. Therefore, the hierarchical structure can be constituted to include plural types of candidate information.
It is preferred that the information retrieving apparatus further includes an output unit for outputting input request information which requests a user to input an input information corresponding to the candidate information belonging to one hierarchy of the hierarchical structures, wherein the output unit includes: a unit for outputting the input request information requesting the input of the candidate information belonging to the (p+1)-th hierarchy if the candidate information belonging to the p-th hierarchy is inputted in response to the input request information requesting the input of the candidate information belonging to the p-th hierarchy (p is a natural number and p less than mxe2x88x921); and a unit for outputting the input request information requesting the input of the candidate information belonging to the (p+q+1)-th hierarchy if the candidate information belonging to the (p+q)-th hierarchy is inputted in response to the input request information requesting the input of the candidate information belonging to the p-th hierarchy (q is a natural number and (p+q) less than mxe2x88x921). This enables the retrieval in the order of the hierarchical structure or alternatively enables the retrieval with jumping between the hierarchies.
In addition, the output unit may further include a unit for outputting the input request information requesting the input of the candidate information in r-th hierarchy (r is a natural number and r less than mxe2x88x921) if no candidate information is inputted for a predetermined time in response to input request information requesting the input of the candidate information belonging to the r-th hierarchy. With this arrangement, if no input in response to the input request information of a hierarchy is made, another input request information of the lower hierarchy is outputted, thereby accelerating the retrieval of the target information.
It a preferred embodiment, the candidate information may include a plurality of candidate information groups each including the plural pieces of the candidate information in one hierarchy, wherein the candidate information included in one candidate information group is different from the candidate information included in another candidate information groups, and wherein, if no input information corresponding to the candidate information is inputted for a predetermined time in response to input request information requesting the input of the candidate information included in one candidate information group, the output unit outputs the input request information requesting the input of the candidate information included in a candidate information group other than the one candidate information group.
With this arrangement, an output of one input request information can be rapidly made. In addition, the desired candidate information can be inputted without the need to output all candidate information in one hierarchy.
The output unit may output the input request information in a form of voice, wherein the information inputted through the input unit is voice information, and wherein the input unit includes a voice recognition unit for recognizing a content of the inputted voice information. This achieves safer and more convenient input of information.
According to another aspect of the present invention, there is provided an information retrieving apparatus for retrieving target information from plural pieces of candidate information, including: a storage unit for storing the plural pieces of the candidate information in a hierarchical structure including a plurality of hierarchies; an input unit for inputting information; a determining unit for determining the candidate information corresponding to the inputted information; and a retrieving unit for retrieving one of the plural pieces of candidate information which belong to the lower hierarchy of the determined candidate information and are associated with the determined candidate information. Consequently, a desired target information can be retrieved conveniently in the information retrieval apparatus.
According to still another aspect of the present invention, there is provided a method of retrieving target information from plural pieces of candidate information composing a hierarchical structure including m hierarchies (m is a natural number not less than 2), wherein the hierarchical structure is arranged such that each piece of the candidate information belonging to (n+1)-th hierarchy (n is a natural number and n less than mxe2x88x921) is associated with one of the plural pieces of the candidate information included in n-th hierarchy, the method including the steps of: receiving voice information; judging a correspondence of inputted voice information with one, of the plural pieces of the candidate information and judging the hierarchy of the candidate information if the correspondence is obtained; and retrieving one of the plural pieces of the candidate information as a target information based on a judged result of the judging step.
In accordance with the apparatus thus configured, the plural pieces of the candidate information are stored in a hierarchical structure including m hierarchies. An input information is received, and then a correspondence of the inputted information with one of the plural pieces of the candidate information is judged. Then, the hierarchy of the candidate information is judged if the correspondence is obtained. Thereafter, one of the plural pieces of the candidate information is retrieved as a target information based on a judgement result.
Therefore, it is possible to retrieve target information in the order of hierarchies, or to retrieve target information while skipping one or plural hierarchies and jumping from a hierarchy to a hierarchy.
The nature, utility, and further features of this invention will be more clearly apparent from the following detailed description with respect to preferred embodiment of the invention when read in conjunction with the accompanying drawings briefly described below.